Carl Friedrich Keil and Franz Delitzsch Old Testament Commentary

With Psa 140:13 the mood and language now again become cheerful, the rage has spent itself; therefore the style and tone are now changed, and the Psalm trips along merrily as it were to the close. With reference to ידעת for ידעתי (as in Job 42:2), vid., Psa 16:2. That which David in Psa 9:5 confidently expects on his own behalf is here generalized into the certain prospect of the triumph of the good cause in the person of all its representatives at that time oppressed. אך, like ידעתּי, is an expression of certainty. After seeming abandonment God again makes Himself known to His own, and those whom they wanted to sweep away out of the land of the living have an ever sure dwelling-place with His joyful countenance (Psa 16:11).